Nu-(acylthiomethyl) carbonylamides and their production



Patented Apr-.8, 1947 UNITED STATES" PATENT OFFICE,

N (ACYLTHIOMETHYL) CARBONYLAMIDES AND THEIR PRODUCTION f William JamesBurke, Marshallton, DeL, assignor to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationMarch 1, 1944,

Serial No. 524,623

Claims. 1

This invention relates to a new class of sulfurcontaining organiccompounds. More particularly, it refers to N -acylthiomethylcarbonamides and to a process for'their preparation.

To the best of my knowledge, N-acylthiomethyl amides as a class are new.

Example I To 380 parts of thiolacetic acid (five mols) is added withstirring 148 parts of N ,N'-bis(methoxymethyDurea (one mol) and one partof concentrated hydrochloric acid in 20 parts of dioxan. The reactionmixture becomes warm and, in a few minutes, a clear solution results.The white crystalline solid which separates out upon cooling is removedby filtration, washed with petroleum ether and recrystallized fromdioxan. In this manner, 190 parts (yield: 81%) of N,N-bis(ace-'tylthiomethyl) urea melting at 162 C. is obtained.

The product is readily soluble in warm dioxan or ethanol andsubstantially insoluble in water. Analysis: Calculated for(CH3COSCH2NH)2CO: N, 11.9%; S, 27.1%. Found: N, 12.1%; S, 27.1%. Thereaction is represented by the following equa tion:

(CHaOCl-IzNH) 2CO+2HSCOCHa- (CHsCOSCHzNH) 2CO+2CH3OHN,N-bis(acetylthiomethyl)urea is soluble in aqueous alkali, e. g.,sodium hydroxide. The alkaline solution, when brought to a pH of 5.0 to8.0 by addition of acetic acid, has the property of reducing thedisulfide linkages of wool or other keratinous materials, as shown bythe strongly positive sodium nitroprusside test (indicative of thepresence of thiol groups) exhibited by wool after the treatment. Thewool so reduced can be 2 treated with an alkylene dihalide such astrimethylene dibromide, which combines with the thiol groups and gives acrosslinked wool of greatly improved resistance to alkali as: comparedwith the original wool.

Example 11 A mixture of 11.6 parts of N,N'-bis(me thoxymethyl) adipamide(0.05 mol), 15.2 parts thiolacetic acid (0.2 mol), 40 parts of dioxanand 0.1 part of concentrated hydrochloric acid is stirred at C. for 30minutes. Forty parts of petroleum ether is added to the resulting clearsolution which is then cooled with ice. The white crystalline product(15.5 parts) is removed by filtration, washed with petroleum ether andrecrystallized from methanol-benzene (50-50). The recrystallized N,N'.-bis acetylthiomethyl adipamide melts at 142 C.; the yield is 83% ofthe theory. The product is readily soluble in dioxan and ethanol andsubstantially insoluble in water.

Analysis: Calculated for CI-IsCOSCHzNHCMCHz) 4CONHCH2SCOCH: Sulfur,20.0%. Found: Sulfur, 19.31%.

Example III 10.8 parts of N-(methoxymethyl) polyhexamethyleneadipamide,which is prepared by reaction of polyhexamethyleneadipamide withformaldehyde and methanol in formic acid solution, and in whichmethoxymethyl substituents are attached to about half of the carbonamidonitrogens, is dissolved in parts of acetic acid, and 6.1 parts ofthiolacetic acid and 0.1 part of p-toluenesulfonic acid are added. Thereaction mixture is stirred at room temperature for two hours, afterwhich 40 parts of methanol is added. The product is precipitated byaddition of water, washed thoroughly with water and acetone to removeunreacted 'thiolacetic acid and dried. Sulfur analysis (4.9%

S) indicates the presence of about one acetylthiomethyl group for eachfour car'bonamido groups.

Films of the N-(acetylthiomethyl)polyhexamethyleneadipamide cast frommethanol water (-10) solution are glass clear and highly elastic. TheN-(acetylthiomethyl) polyhexa methyleneadipamide is readily hydrolyzedby alcoholic potassium hydroxide to yield an N-mercaptomethyl derivativewhich becomes insoluble in product redissolves upon treatment with analcoholic solution of ethyl mercaptoacetate. The reactions which occurare illustrated by the following skeletonized equations:

A 50% solution of a butanol modified ureaformaldehyde resin in butanolis diluted with an equal volume of benzene and the resulting mixture ispoured with stirring into petroleum ether. The finely divided whitesolid is washed thor oughly and dried. The modified urea-formaldehyderesin thus obtained in the dry state is, according to present knowledge,characterized by the presence of recurring units having the for- To asolution of 158 parts of the above solid in 800 parts of benzene isadded 114 parts of thicl acetic acid and one part of concentratedhydrochloric acid in 20 parts of dioxan. After 30 rninco NH l lH J mocanC IHZSCOCHa Example V To 38 parts of N-methylolbenzamide dissolved in 70parts of dioxan is added 38 parts of thiolacetic acid and 20 parts ofdioxan containing one part of concentrated hydrochloric acid. Thereaction mixture is heated for 30 minutes at 70 C.,

then concentrated under reduced pressure. The resulting solid afterrecrystallization from benzene-petroleum ether melts at 72-74 C. Theyield of N-acetylthiomethylbenzamide is 40 parts, or 76% of the theory.The product is readily soluble in alcohol, benzene, chlorinated solventsand aqueous alkali and only slightly soluble in water. Analysis:Calculated for CsHsCONHCHzSCOCI-b s,'15.3%. Found: s,14.4%.

Example VI To 3.9 parts of crystalline, monomeric tris(ethoxymethyDmelamine (prepared as described in McGrews application S.N. 387,771) is added 4 6.84 parts of thiolacetic acid and 2 parts 0!.dioxan containing 0.1 part or concentrated hydrochloric acid. After 15minutes at room temperature the mixture is warmed to C., whereupon aclear solution results. A white crystalline product is obtained byadding eight parts of petroleum ether and allowing the solvent andexcess thiolacetic acid to evaporate at room temperature. Afterrecrystallization from a methanol-benzene mixture, the reaction productmelts at 134-138 C. and contains 19.46% of sulfur, which indicates thatsomewhat more than two of the ethoxymethylamino groups have beenreplaced by acetylthiomethylamino groups.

Instead of the crystalline, monomeric tris.

(ethoxymethyl) -melamine, there maybe used the resinous product obtainedby reacting melamine, formaldehyde and alcohol at elevated temperatureas described in U. S. Patent 2,197,357, in which case the reactionproduct is resinous rather than crystalline.

In the process of this invention there may be employed any monobasiccarbothiolic' acid, among which may be mentioned thiolpropionie,thiolbutyric, thiollauric, thiolbenzoic acids, etc. Of these, thesaturated lower aliphatic carbothiolic acids, 1. e., those containing upto six carbon atoms, are preferred. Thiolacetic acid is the outstandingrepresentative of this class since it is the cheapest and most availablecarbothiolic acid.

The process ,of this invention is applicable to any desiredN-alkoxymethylcarbonamide. In addition to those illustrated in theexamples, there may be mentioned the N-alkoxymethyl derivatives ofacetamide, propionamide, butyramide, lauramide, palmitamide, stearamlde,chloracetamide, cyclohexylacetamide, nicotinamide, N- ethylpropionamide,maleamide, undecylenamide, thioacetamide, urethane, etc. There may beused also the monoor poly-N-alkoxymethyl derivatives of polyfunctionalamides such as'oxamide, glutaramide, sebacamide, phthalamide,phthalimide, etc. Other compounds which lend themselves readily to theprocess of this invention are the monoor bis-alkoxymethyl derivatives ofopen chain ureas such as urea itself, thiourea, N- methylurea,N-phenylurea, N-phenylthiourea. guanidine, N-ethylguanidine, or ofcyclic ureas. Among the latter may be mentioned the N,N'-bis(alkoxymethyl)urons, e. g., N,N'-bis(methoxymethyl) uron, thetetrahydro 1,3 bis(a1koxymethyl) triazones, e. g.,tetrahydro-1,3-bis(methoxymethy1)-5-methyl 2(1) triazone, and theN,N-bis(alkoxymethyl).ethylieneureas, e. g., N,N'-

bis(ethoxymethyl) ethyleneurea and the corresponding ethylenethioureaderivative, 'aminotriazine derivatives such as2,4,6-tris(methoxymethylamino)-1,3,5-triazine, etc. In addition,polymeric amides such as the N-alkoxymethyl polyamides, orpolyesteramides, the urea-formaldehyde resins, the dicyandiamideformaldehyde 7 resins, etc., may be used to yield polymeric N-acylthiomethyl amides. The N-alkoxymethyl derivatives of oxygencarbonamides are the most suitable materials for the process of thisinven- Alkoxymethyl derivatives of urea are described,v

for example, in U. S. Patent 2,254,001; alkoxymethyl derivatives ofdicarbonamides are described in the McGrew application S. N. 360,835;

cyclic urea derivatives such as methylolurons are described by Kadowakiin Bull. Chem. Soc. J apan,

11, 248, (1936); many alkoxymethyl triazine derivatives are shown in U.S. Patent 2,197,357.

The process is in general somewhat easier to carry out with the N-alkoxymethyl amides than with the N-hydroxymethyl amides. f the N-alkoxymethyl amides, those in which the alkoxy group is that of a loweraliphatic alcohol, i. e., an alcohol having up to six carbon atoms, arepreferred since removal of the alcohol which is formed during thecondensation is easier. The N-alkoxymethyl oxygen carbonamides in whichthe alkoxy group is methoxy, ethoxy, propoxy or butoxy are the preferredspecies.

The process can be carried out at any desired temperature up to thedecomposition point of the reactants, but, in general, a temperaturebetween about C. and about 100 C. is preferred. A catalyst is notessential though it is in general desirable to use small amounts of anacidic catalyst such as hydrochloric acid, sulfuric acid,ptoluenesulfonic acid, ammonium chloride, phosphoric acid, etc. Asolvent is not necessary but is often desirable since the presence of asolvent facilitates intimate contact of the reactants. Any inert solventsuch as benzene, dioxane, ether, toluene, etc., may be used. Excesscarbothiolic acid, e. g., thiolacetic acid, is conveniently used as asolvent, alone or mixed with another solvent.

Th N-acylthiomethyl amides of this invention are particularly valuableas intermediates in the preparation of N-mercaptomethyl carbonamides byhydrolysis of the acylthio groups. They are also useful per se aspetroleum chemicals and pharmaceuticals. The polymeric acylthiomethylamides are useful as films and fibers and as ingredients of coatingcompositions.

The above description and examples are intended to be illustrative only.Any modification thereof or variation therefrom which conforms to thespirit of the invention is intended to beincluded within the scope ofthe claims.

What is claimed is:

1; N,N'-bis acetylthiomethyl) urea.

2. An N- (acetylthiomethyllurea.

3. An N- (acetylthiomethyl) adipamide.

4. N ,N '-bis (acetylthiomethyl) adipamide.

5. N (acetylthiomethyl) benzamide.

6. An N-(acetylthiomethyl)carbonylamide, the carboxylic acid radical ofsaid amide being ofv one to seven carbon atoms.

7. An N-(acetylthiomethyl)carbonylamide, the carboxylic acid radical ofsaid amide being aromatic and of one to seven carbon atoms.

8. An N-(acetylthiomethyl)carbonyla'mide, the carboxylic acid radical ofsaid amide being allphatic and of one to seven carbon atoms.

9. Process for preparing N (acetylthiomethyl) carbonylamides whichcomprises reacting thiolacetic acid in an anhydrous system with an N-alkoxymethylcarbonylamide, the alkyl of the alkoxy group being of one tosix carbons and the carboxylic acid radical being of one to seven carbonatoms.

10. Process for preparing N-(acetylthiomethyDcarbonylamides whichcomprises reacting thiolacetic acid in an anhydrous system with anN-alkoxymethylcarbonylaniide, the alkyl of the alkoxy group being of oneto six carbons and the carboxylic acid radical being aromatic and of oneto seven carbon atoms.

11. Process for preparing N-(acetylthiomethyl)carbonylamides whichcomprises reacting thiolacetic acid in an anhydrous system with anN-allcoxymethylcarbonylamide, the alkyl of the alkoxy group being of oneto six carbons and the carboxylic acid radical being aliphatic and ofone to seven carbon atoms,

12. Process of claim 9 wherein an acidic catalyst is employed.

:13. Process for preparing N,N'-bis(aoetylthiomethyl) urea whichcomprises reacting thiolacetic acid with N,N'-bis .(methoxymethyllureain anhydrous dioxan containing one part, per 20 parts of dioxan, ofconcentrated hydrochloric acid.

14. Process for preparing N,N'-bis (acetylthiomethyl) urea whichcomprises reacting thiolacetic acid with N,N-bis (methoxymethyllurea inan anhydrous inert liquid organic solvent.

15. Process for preparing N,N-bis(acety1thiomethyl) adipamide whichcomprises reacting N,N'-bis(methoxymethyl) adipamide and thiolaceticacid in an anhydrous inert solvent.

WILLIAM JAMES BURKE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Ellis Feb. 23, 1932

